Re: [RFC PATCH v6 4/9] vfs: lookup_open(): move setting FMODE_CREATED up when calling create()

[Christian Brauner]

On Mon, Jun 01, 2026 at 12:34:40PM +1000, NeilBrown wrote:
> On Mon, 01 Jun 2026, Jori Koolstra wrote:
> > In preparation for using vfs_create_no_perm() in lookup_open() we need
> > to move setting FMODE_CREATED on the file mode to either before or after
> > that call, as currently it is in the middle. If try_break_deleg() fails
> > it is currently not set, but vfs_create_no_perm() includes a
> > try_break_deleg().
> > 
> > Going up the call chain of lookup_open() we see that it is only used in
> > open_last_lookups() if no error is returned from lookup_open(), so we
> > can safely move it to after the filesystem create() call. This also
> > makes more sense when reading the code as you don't have to wonder what
> > the implications are of setting FMODE_CREATED before the create() call.
> 
> It seemed a bit odd to me that we set FMODE_CREATED before actually
> creating.

Plus, we kinda-sorta-maybe do expose that as uapi - even though it's
broken on networking filesystems... which I didn't know in that detail
back then. So be prepared to whack me over the head with:

820a185896b77814557302b981b092a9e7b36814


> It doesn't matter as FMODE_CREATED is only meaningful if no error has
> been reported, and if create doesn't end up happening, then there must
> be an error.
> 
> So I like this improvement.

Agreed.